TFE is a superior-grade, non-hardening, heavy-duty pipe thread sealant that is easy to-apply. Formulated to a thick paste consistency, its fortified with an extra amount of PTFE and PTFE materials to give a positive seal with less effort. Because of its unique solids content, TFE fills thread imperfections and provides leak-proof joints that seal for the life of the connection. Not for use on oxygen systems.